Project Summary: In severely resource-limited rural settings, scale-up of services to eliminate mother-to-child transmission of HIV (EMTCT) has failed to provide effective HIV testing and antiretroviral therapy (ART) coverage for women in highest prevalence southern African regions. All HIV-infected pregnant women are now eligible for life-long antiretroviral therapy (ART), regardless of CD4+ cell count (Option B+) but retention among women enrolled through Option B+ programs remains sub-optimal. In sub-Saharan Africa (SSA) it is common for women to require male partner approval to access and remain engaged in HIV-related health services. Despite the likelihood that male involvement would improve program coverage and adherence, the evidence base for effective interventions to involve male partners in HIV testing and treatment through ANC point of care is very limited. Furthermore, whether such strategies are indeed cost-effective for improving outcomes of HIV- diagnosis and treatment in pregnancy is unknown. Our proposal seeks to address these key gaps in the evidence base and guide scale-up by evaluating a promising male engagement intervention (?Homens para Sade? (HoPS)+ [Men for Health]) targeting EMTCT in Mozambique through a clinic-randomized trial. We will engage 24 ANC clinics; 12 intervention and 12 standard of care, with 40 HIV-infected couples per clinic where currently >60% of couples attend their first ANC visit together. The planned intervention addresses social- structural and cultural factors influencing EMTCT through the creation of couples-centered integrated HIV services, including: (1) ANC-based couples HIV testing, ART enrollment, and care for sero-concordant HIV+ expectant couples; (2) Couple-based treatment in the post-partum period; (3) Couple-based education and skills building; and (4) Treatment continuity with the support of expert-patient (peer) supporters from couples who have successfully navigated EMTCT. Given that 8.0% of all pregnant women and 7.2% of their partners tested HIV-positive during ANC visits in 2015 (FGH monitoring and evaluation [M&E] data), our pioneering work in Mozambique's rural Zambzia province suggests that innovative strategies are essential to engaging HIV-infected male partners in antenatal care (ANC) in order to achieve EMTCT and to improve substantially the health of the mothers. Our team of Mozambican and U.S. investigators has a proven record of international HIV research success and we have specific recent experience with EMTCT cluster randomized trials, male-engagement in ANC services, and cost-effectiveness analysis of HIV programs. The specific aims of this study are: (1) To implement and evaluate the impact of male-engaged, couples-centered services on retention in care, adherence to ART, and early infant diagnosis among HIV+ pregnant women and their HIV+ male partners through a cluster-randomized RCT; (2) To investigate the impact of HoPS+ on hypothesized mechanisms of change; and (3) To use validated simulation models to evaluate cost-effectiveness of the HoPS+ intervention with the use of programmatic provincial M&E data and data from our trial results.